Should a submersible water well be bonded to the utility grounding system?

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11bgrunt

Pragmatist
Location
TEXAS
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Electric Utility Reliability Coordinator
3 phase water well. POCO has overhead Ungrounded Y primary, 240 volt delta bank, 3 pots.
Secondary also serves the house. Pump motor is set at 320’.
Two Pump motor losses in the last month. Both associated with nearby lightning strikes.
Utility replaces one blown transformer fuse on the bank each time and power is restored.
I can see no grounding conductor headed down the hole.
Is a bond required and if installed, would it make any difference?
 
3 phase water well. POCO has overhead Ungrounded Y primary, 240 volt delta bank, 3 pots.
Secondary also serves the house. Pump motor is set at 320’.
Two Pump motor losses in the last month. Both associated with nearby lightning strikes.
Utility replaces one blown transformer fuse on the bank each time and power is restored.
I can see no grounding conductor headed down the hole.
Is a bond required and if installed, would it make any difference?
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These sections suggest the casings would need to be part of the GES which would pretty much bond them.

I don't see anywhere there is a well pump exception to the requirement to run an EGC with circuit conductors, although for some reason I am unable to find that requirement in the code right this second.

My personal opinion is that bonding the pump motor probably would not have saved it from a lightning strike anyway. The lightning probably came in on the power lines and no amount of bonding would change that.

Some kind of surge or lightning suppressor might help.

Curious. Is it common for a lighning strike to open just one fuse?
 
With this type of transformer bank, the primary coils are not connected to the utility system neutral.
The secondary does have a nutral connected on the center tap of one transformer. The three phase overhead primary does have a fused single phase tap breaking off to serve another property.
All arrester protection is transformer tank mounted and below the primary fuse.
 
Are there appropriately sized heaters or overload relay settings to protect the pump motor from single-phasing when the primary fuse blows?
 
Is there a grounding conductor going to the well case?

The well case is a great grounding electrode. If this is not bonded to the rest of the GEC, then you can have a situation where the _separate_ ground electrodes end up at different potential due to soil currents caused by nearby lighting strikes. Current can flow into one electrode, through equipment, and out the other electrode.

Separate grounding electrodes tied together via equipment essentially become 'soil antennas' coupling soil currents _through_ your equipment.

-Jon
 
Is there a grounding conductor going to the well case?

The well case is a great grounding electrode. If this is not bonded to the rest of the GEC, then you can have a situation where the _separate_ ground electrodes end up at different potential due to soil currents caused by nearby lighting strikes. Current can flow into one electrode, through equipment, and out the other electrode.

Separate grounding electrodes tied together via equipment essentially become 'soil antennas' coupling soil currents _through_ your equipment.

-Jon
the only current path in such a case would be thru the earth and it is not that great of a current path.
 
the only current path in such a case would be thru the earth and it is not that great of a current path.
There is no EGC connected to the steel case or any of the J boxes at the well head. In the past I have interpreted the rule as case should be bonded and the pump motor
The control does use a Siemens ESP200 overload relay that is dialed in just above FLA.
This is a 7.5HP pump motor.
the only current path in such a case would be thru the earth and it is not that great of a current path.

There is no EGC connected to the steel well casing or any of the metal J boxes at the well head. In the past I have interpreted the rule as the well casing and the pump motor in the hole should be bonded to the EGC. Almost all water wells I have seen in the last 20 years were cased with PVC until 10' from the top.
The control does use a Siemens ESP200 overload relay that is dialed in just above FLA.
This is a 7.5HP pump motor.
Usually electricians and well guys have different opinions about all this.
 
the only current path in such a case would be thru the earth and it is not that great of a current path.

You are exactly right if you are talking about the fault current path for the supplied electrical power. But I am looking at this from the other side of the coin, how the system will respond to lightning discharge currents flowing through the soil.

If you have two ground electrodes, _not_ bonded together, but each connected to equipment sharing power wiring, then lightning current which is trying to flow through the soil could instead flow via one electrode, through the system bonding, along the power wiring, then through the insulation at the equipment and to the second grounding electrode. The path through the earth is not as good as the path through the power wiring, with the exception of the insulation at one end...and if the voltage is high enough it can bust through that.

-Jon
 
I am a master electrician and was a pump and irrigation plumber for a while, worked a lot on submersibles, installing electrical services and way back worked as a helper on a cable tool drilling rig, lots of experience with wells, lightning, not so much
1. The drop cable to the well has an EGC, right?
2. For lighting and HV tansients, a good place to start is with SPDs on the service. "You get what you pay for, and more is better" Mike Holt said that.
I would install a Leviton 42120-DY3 at the service panel. Expensive, yes but look at the cost to pull and replace the well pump. And your next one may be a VFD will pump...SPDs are good place to start
3. Make sure all your electrodes (well casing), ground rods, and water pipes are bonded together. If you don't and there is a nearby lighting strike, there will be voltage in the earth, the two electrodes will be a different potential, which means current flow, thru your equipment, as winnie pointed out above.

A direct lighting strike at the pump house, not sure if you could protect against damage from that.
 
Is this services delta secondary a center tap grounded, corner grounded or ungrounded? And is the service grounded and bonded properly for the type of service?
Also, the metallic well casing must be attached to the EGC per 250.112(M).
You mention having ungrounded metallic J boxes as well. Sound like red flags for lots of violations in this install.
 
I am a master electrician and was a pump and irrigation plumber for a while, worked a lot on submersibles, installing electrical services and way back worked as a helper on a cable tool drilling rig, lots of experience with wells, lightning, not so much
1. The drop cable to the well has an EGC, right?
2. For lighting and HV tansients, a good place to start is with SPDs on the service. "You get what you pay for, and more is better" Mike Holt said that.
I would install a Leviton 42120-DY3 at the service panel. Expensive, yes but look at the cost to pull and replace the well pump. And your next one may be a VFD will pump...SPDs are good place to start
3. Make sure all your electrodes (well casing), ground rods, and water pipes are bonded together. If you don't and there is a nearby lighting strike, there will be voltage in the earth, the two electrodes will be a different potential, which means current flow, thru your equipment, as winnie pointed out above.

A direct lighting strike at the pump house, not sure if you could protect against damage from that.

All piping is PVC.
There is no EGC in the drop cable.
There is a little Delta brand 277-480 arrester connected at the breaker panel serving the control.
The Delta secondary bank is center tap grounded. 120-120-208 HL. 240V P-P.
The SPD addition will probably be a hard sell since the well man added the Delta brand arrester.
Three phases to the control and three phases down the hole. No EGC anywhere near the well.
The residential service fed by this transformer bank is set up fine with no reported problems.
Voltage recordings today show no PQ issues.
 
All piping is PVC.
There is no EGC in the drop cable.
There is a little Delta brand 277-480 arrester connected at the breaker panel serving the control.
The Delta secondary bank is center tap grounded. 120-120-208 HL. 240V P-P.
The SPD addition will probably be a hard sell since the well man added the Delta brand arrester.
Three phases to the control and three phases down the hole. No EGC anywhere near the well.
The residential service fed by this transformer bank is set up fine with no reported problems.
Voltage recordings today show no PQ issues.
Sounds like an installation that is an electrocution waiting to happen. Improperly wired pumps/wells have killed a number of people.
Most well installation people don't have even a basic understanding of compliant grounding and bonding. A fault return path is a foreign concept.
 
Sounds like an installation that is an electrocution waiting to happen. Improperly wired pumps/wells have killed a number of people.
Most well installation people don't have even a basic understanding of compliant grounding and bonding. A fault return path is a foreign concept.
could be pricey to pull the pump and replace the drop cable. although it might be just 3 wires twisted together. maybe you could twist an EGC over the outside. still pricey.
 
I don't have the story from the POCO other than one transformer fuse and the fuse protecting the single phase tap each time.
The Red Herring; there are two tall radio antenna/cell towers served on the single phase tap by two different transformers. The towers did not suffer in the recent event except loss of power when that single phase tap fuse blew during the storm.
 
The Red Herring; there are two tall radio antenna/cell towers served on the single phase tap by two different transformers. The towers did not suffer in the recent event except loss of power when that single phase tap fuse blew during the storm.
May not be a red herring since the radio towers could've coupled induced lightning currents into the system even if they didn't suffer a direct hit.
 
... A direct lighting strike at the pump house, not sure if you could protect against damage from that.
Of course you could. It's just a question of risk and budget.
Several lightning rods, installed on their own towers encircling the pumphouse (a'la Stonehenge) and taller than the pumphouse will prevent a direct lightning strike at the pumphouse, and its own grounding system could dissipate the energy harmlessly.

Just sayin' it's possible ... not recommending such a drastic step. (yet)
It sounds like correcting all the installation errors will go a long way toward a safe & reliable system.
 
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